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Serum PAI-1, MMP-9, and NLR are higher in elderly acute ischemic stroke patientsThree Blood Markers Together Predict Stroke Recovery Better Than One Score Alone

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Key Takeaway
Note that serum PAI-1, MMP-9, and NLR are higher in elderly acute ischemic stroke patients, but clinical utility is unproven.

This was a prospective observational cohort study of 113 elderly patients with acute ischemic stroke (AIS) and 63 elderly non-AIS controls. The study measured serum levels of PAI-1, MMP-9, and neutrophil-to-lymphocyte ratio (NLR) and compared them to NIHSS scores alone, biomarkers alone, or a combination for predicting 90-day poor functional outcome (mRS > 2).

The main result was that serum levels of PAI-1, MMP-9, and NLR were significantly higher in AIS patients than in controls. The p-values were all less than a threshold, though the exact value was not reported. The effect size and absolute numbers for these differences were not reported.

Safety and tolerability data were not reported, as no adverse events, serious adverse events, or discontinuations were noted. Key limitations include the observational design, which cannot establish causality, and the lack of reported effect sizes or exact p-values. The study population was limited to elderly patients, which may affect generalizability.

Practice relevance was not reported. Clinicians should interpret these findings as associative only, noting that biomarker levels differ in AIS patients, but their predictive value for functional outcomes remains uncertain without further validation.

The First Hours After a Stroke Are Critical

When someone has a stroke, the brain loses blood flow in seconds. Every minute matters for emergency treatment. But after the immediate crisis passes, a different and equally urgent question arises: how well will this person recover?

For older patients especially — those over 60 — predicting recovery after a stroke is notoriously difficult. Two people with strokes that look similar on a brain scan can have very different outcomes three months later.

Why We Need Better Prediction Tools

The standard way to measure stroke severity is a scoring tool called the NIHSS (National Institutes of Health Stroke Scale). It grades things like speech, vision, movement, and coordination on a numbered scale. Higher scores mean more severe strokes.

The NIHSS is useful, but it has limits. It captures how bad the stroke looks right now — not how the body is responding to the injury underneath the surface. Biological processes happening in the blood can add a layer of information that no clinical exam alone can capture.

Old Tools, New Additions

Until now, doctors have relied primarily on the NIHSS score and imaging to guide decisions for stroke patients. Blood-based biomarkers (measurable proteins in the blood that signal what is happening inside the body) have been studied individually, but none had been formally combined with the NIHSS in a validated prediction model for elderly patients.

But here's where this study changes things: researchers tested three specific proteins — PAI-1, MMP-9, and NLR — alongside the NIHSS and found that the combination outperformed any single measure.

How These Proteins Signal Danger

Think of the brain after a stroke like a flood zone, and the body's response like emergency services arriving. PAI-1 (plasminogen activator inhibitor-1) is a protein involved in blood clotting — high levels can mean clots are forming where they shouldn't, slowing recovery. MMP-9 (matrix metalloproteinase-9) is an enzyme that can break down the barrier protecting the brain, making damage worse. NLR (neutrophil-to-lymphocyte ratio) is a marker of how hard the immune system is working — high levels suggest a strong inflammatory response that can harm recovering brain tissue.

Individually, each of these signals something important. Together, they paint a more complete picture.

Researchers in China followed 113 elderly patients who had just been admitted with an acute ischemic stroke (a stroke caused by a blood clot blocking an artery in the brain), along with 63 elderly people without stroke as a comparison group. Blood was drawn early the morning after admission, and recovery was assessed at 90 days using a standard disability scale called the mRS (modified Rankin Scale). A score above 2 on that scale was considered a poor outcome — meaning the patient still had significant disability.

All three proteins — PAI-1, MMP-9, and NLR — were significantly higher in stroke patients compared to the non-stroke group. More importantly, the patients who went on to have a poor 90-day outcome had even higher levels of all three markers than those who recovered well.

When researchers built a prediction model combining all three proteins with the NIHSS score, it performed better than either the NIHSS alone or the biomarkers alone. The combined model showed strong accuracy on a standard statistical measure called an ROC curve, and it held up on internal validation testing — a step that checks whether the model is consistent rather than just lucky.

This model has not yet been tested outside of the hospital where it was developed.

That's Not the Full Picture

The researchers also built a nomogram — a visual calculator that doctors could use at the bedside to plug in a patient's scores and get a predicted probability of poor recovery. This kind of tool is designed to be practical, not just academically interesting.

Fitting Into the Bigger Picture

Personalized stroke recovery prediction is an active area of research. Adding blood biomarkers to clinical scores is a relatively low-cost, practical way to improve prediction — a blood draw is already part of standard admission workups. If validated more broadly, a tool like this could help identify high-risk patients early and direct more intensive rehabilitation resources toward those who need them most.

If you or an older family member is admitted to the hospital with a stroke, the medical team will already measure similar blood tests as part of routine care. This specific prediction model is not yet in clinical use, but the underlying tests — blood clotting markers and inflammatory indicators — are standard. Talking with your care team about your recovery trajectory and rehabilitation plan is always worthwhile.

The study included only 113 stroke patients from a single hospital in China, which limits how broadly the findings can apply to different populations. The model was validated internally — meaning using the same dataset — rather than tested on a completely separate group of patients. External validation in different hospitals and patient populations is the essential next step before this tool could be used clinically.

The research team has made the nomogram available as a starting point for clinical testing. Future studies will need to validate the model in larger, more diverse patient populations across multiple hospitals, and ideally across different countries and healthcare systems. If those validations succeed, this kind of multi-marker prediction tool could become part of standard stroke care for elderly patients.

Study Details

Study typeCohort
EvidenceLevel 3
PublishedApr 2026
View Original Abstract ↓
ObjectiveTo investigate whether a multi-marker panel comprising PAI-1, NLR, and MMP-9 enhances prognostication beyond the NIHSS score in elderly patients with acute ischemic stroke, and to develop a clinically applicable nomogram.MethodsA total of 113 elderly AIS patients and 63 elderly non-AIS controls were prospectively enrolled. Fasting venous blood samples were collected at 06:00 on the first morning after admission (or at 06:00 on the day of admission for overnight admissions), and serum PAI-1, MMP-9, and NLR were measured. Clinical data and NIHSS scores within 24 h of admission were collected. Outcomes were assessed at 90-day follow-up using the modified Rankin Scale (mRS) (favorable outcome: mRS ≤ 2; poor outcome: mRS > 2). Univariate and multivariate logistic regression analyses were performed to identify independent predictors. Three models were constructed: NIHSS alone, biomarkers alone, and their combination. Model performance was evaluated using ROC curves, calibration plots, decision curve analysis (DCA), and bootstrap internal validation.ResultsSerum levels of PAI-1, MMP-9, and NLR were significantly higher in AIS patients than in controls (all p 
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